Onshore exploration and development work in Australia, although not as active as offshore E&D, is providing interesting niche opportunities, especially for smaller companies.
There continues to be hope of making commercial finds in Western Australia's onshore Carnarvon basin-site of Australia's first post-World War 11 oil discovery, Rough Range in 1953. An oil play is under way in the Canning basin, and gas finds are the focus elsewhere in Western Australia.
However, only two onshore regions in Australia stand out with concentrated and consistent E&D programs: the Cooper-Eromanga and Surat/Bowen basin complexes,
WESTERN AUSTRALIA
None of the recent efforts in the onshore Carnarvon basin have yielded a commercial oil field, although there remains hope for the Mardie heavy oil discovery near the coast north of Onslow, W.A.
A group headed by Stirling Petroleum is calling on U.S. expertise in heavy oil recovery to examine feasibility of a development project.
Further north, in the onshore Canning basin a group of small firms headed by newcomer Anzoil is returning to the West Kora oil discovery in low lying coastal flats near the town of Derby.
The field produced a little more than 15,000 bbl of oil before high water cut forced a shut-in during 1990, The group plans to pump test the known oil zone before testing a higher zone within the same formation in the original well.
The main onshore success in Western Australia has come with the start of production from Tubridgi gas field near Onslow in September 1991.
A group headed by Devex unit Doral Resources and Pan Pacific Petroleum spent $23 million (Australian) to commence production from the 1980 discovery.
Up to 21.4 MMcfd of gas is flowing via a 92 km spur line connecting to the main onshore trunk pipeline taking gas from the offshore Northwest Shelf gas project to Western Australia's southwestern region.
Reserves are pegged at 147 bcf. Perhaps equally important is the fact that Tubridgi facilities are ideally placed to assist in transport of gas from a number of the new discoveries in the offshore Carnarvon basin, including Griffin and Roller.
The other interesting new development in onshore Western Australia is Beharra Springs gas field in the Perth basin close to the mature Dongara gas development operated by West Australia Petroleum Pty. Ltd.
Beharra Springs, now operated by Sagasco Resources, was discovered in April 1990 and is estimated to contain 62.7 bcf of reserves. Initial problems in removing hydrogen sulfide from the gas have been overcome, and the field is now flowing at 4 MMcfd. The field is producing into the existing Dongara-Perth gas line.
COOPER-EROMANGA
The Cooper-Eromanga basin of northeastern South Australia and southwestern Queensland is the most active onshore Australia area this year, with plans for as many as 40 exploratory and appraisal wells.
Discoveries of oil and gas there are not large, but they are reasonably frequent and help to maintain flow rates.
In the South Australian sector, current production is about 20 000 b/d of crude oil, about 8,000 b/d of condensate, and 12,000 b/d of natural gas liquids.
Gas is produced to supply the South Australia and New South Wales markets.
In the Queensland sector, oil production is about 18,000 b/d, with a minor contribution from condensate and none from NGL.
However, earlier this year a green light was given to a long awaited project to develop the Southwest Queensland gas/condensate fields. The $120 million (Australian) project, operated by Santos, involves construction of a gas plant and gathering system for multiple field gas reserves totaling 900 bcf. An initial phase, to go on stream in January 1994, will develop Ballera, Munka, Yanda, and Challum fields.
Plans call for installing facilities for gas compression and transport of gas from Ballera field, south of the main oil facility at Jackson, in Queensland to Moomba gas plant in South Australia via an 180 km trunk line. The Ballera plant will separate condensate from the gas stream and send it to Jackson to be incorporated with the region's crude oil flowing by pipeline to Brisbane on Queensland's east coast. Gas will go to Moomba where NGL will be extracted and sent on by existing pipeline to the Port Bonython terminal on Spencer Gulf. Dry gas will be fed into the trunk line to supply the Adelaide market.
In the Cooper-Eromanga basin of South Australia, there are no similar major projects planned. However, extensions to existing gas and crude oil gathering systems are expected to continue at about 25 well connections/year. The estimated annual development cost in this area is $20-30 million (Australian)/year. In the coming year, another $15 million (Australian) outlay is expected with addition of several field compression stations.
SURAT/BOWEN
The Surat/Bowen basins will host 20-30 exploratory wells this year, but there are no development projects planned on the scale of those in the southwestern part of the state.
Of interest elsewhere in Queensland is the attempt by Energy Equity, Perth, to prove 80 bcf of gas reserves in Gilmore gas field in the-central part of the state for use in electricity generation.
The $5.5 million (Australian) project involves drilling new wells and reentering some original wells in the field, discovered in the 1960s but regarded then as uneconomic. The plan calls for the reserves to fulfill a $400 million (Australian), 20 year contract with the Queensland Electricity Commission for gas to be transported about 100 km via pipeline to supply a power station to be built at the town of Blackall.
Copyright 1992 Oil & Gas Journal. All Rights Reserved.
